Yoy . Dental braces are devices made of plastic and metal that are glued onto your teeth to help straighten them. Not only are they uncomfortable, but they also get dirty easily and make teenagers feel ugly 2 In order to solve some of these issues, grad students at Stanford invented clear, removable plastic aligners in 1997. Since Invisalign aligners are substitutes for traditional braces and use less metal than traditional braces, the new Invisalign technology freed up more metal. Therefore, the ;. (Supply/Demand) in traditional braces has increased At the same time, the increasing availability of Invisalign aligners meant that the braces has been decreasing. The market therefore ends up in zone Ay (1/2/3/4) where the equilibrium price A, (higher/lower/unknown) and the equilibrium Quantity is (higher/lower/unknown)